THE EFFECT OF HEAT TREATMENT ON THE STRUCTURE AND PROPERTIES OF CHROMIUM LOW-ALLOY WEAR-RESISTANT CAST IRON ChKh3

10.25712/ASTU.1811-1416.2023.01.011

Abstract

The paper presents studies of the effect of heat treatment on the microstructure, microhardness and structural-phase state of chromium low-alloy wear-resistant cast iron ChKh3 samples. Metallographic analysis was carried out using «Carl Zeiss Axio Observer Z1m» metallographic microscope and the «ThixoMet PRO» software package. Thermal treatment of the samples was carried out in a chamber thermal furnace of the SNOL type equipped with a PID controller «Termodat 16-E3». The heating temperature for quenching was 890 °C, holding at this temperature for 2 h, after which the samples were removed from the furnace and cooled in still air. After cooling to a temperature of 40-50 °C, the specimens were tempered at a temperature of 180-200 °C for 2 h. The studies performed have shown that during heat treatment, the main contribution to the increase in the hardness of wear-resistant chromium cast iron ChKh3 is made by a significant increase (by 2-2.5 times) the hardness of the metal matrix as a result of solid solution hardening and partial precipitation of fine inclusions in it of carbide particles. Tests of heat-treated shot blast blades made of cast iron ChKh3 showed an increase in service life by 8-11 times compared to cast blades not subjected to heat treatment, and 1.5-2 times higher compared to serial shot blast blades, made of cast iron 510Cr2, supplied from China.